Aortic valve stenosis

ecg monitoring

What is aortic valve stenosis?

Aortic valve stenosis is a condition marked by narrowing of the aortic valve. This condition limits the amount of blood flowing from the left ventricle to the aorta and then to all other parts of the body.

The obstruction of the aortic valve will exert increased pressure on the heart, making the heart muscles weak. Aortic valve stenosis is a common disease of the heart valves, requiring intense investigations for diagnosis. It can be managed through a range of valve dilatation techniques to surgical replacement of the valve.

Aortic valve stenosis

Aortic valve stenosis

Causes and risk factors

Causes

Causes of aortic valve stenosis can be:

  • Congenital defect in heart: There are three flap-like tissue leaflets which form the aortic valve. Some children often by birth, will have 1, 2 or 4 tissue leaflets than the usual 3. Such deformities will result in narrowing or other problems of the valve in the adulthood, requiring repair or replacement.
  • Calcium accumulation: Calcium present in the blood can get deposited on the valves with ageing. Such deposition usually is not a matter of concern, however, in some individuals especially with congenital defects in the heart, the deposits may lead to stiffening and subsequent narrowing of the valve. It generally occurs in older individuals.
  • Rheumatic fever: A streptococcus throat infection can sometimes lead to rheumatic fever over a period. Rheumatic fever can cause scar tissue formation on the valve and narrow it, ultimately causing aortic valve stenosis. Calcium deposition can occur on such scar tissue and subsequently lead to aortic valve stenosis.

 

Symptoms and signs

The symptoms of aortic valve stenosis arise when there is a severe narrowing of the valve. These symptoms may include:

  • Fatigue
  • Shortness of breath
  • Dizziness
  • Chest pain
  • Palpitations (Increased awareness of one’s own heart beats)

On examination, there may be varying features of left ventricular enlargement, unusual heart sound (murmur) and heart failure.

Diagnosis

The physician will review the medical history and do a physical examination; check for the heart murmur, an unusual sound of the heart. This sound results from the uneven blood flow via the narrowed aortic valve.
A cardiologist may recommend the following tests on suspecting aortic valve stenosis:

  • Echocardiogram: The image of the heart is produced using sound waves. An echocardiogram will help the doctor in detecting anomalies in the heart valves or the walls. It will be helpful in deciding the apt treatment approaches and to monitor the treatment as well.
  • Electrocardiogram (ECG): Wires with patches are affixed to the chest wall for detecting the heart’s electrical impulses. The output is in the form of waves. Enlargement or thickening of the left ventricle can be diagnosed by ECG, which occurs in aortic valve stenosis.
  • X-ray of the chest: The size and shape of the heart can be known by an x-ray of the chest. The left ventricle enlargement can also be assessed. X-rays can show calcium deposits also.
  • Exercise tests: These are performed to assess the tolerance levels upon exercising and the heart response.
  • Magnetic resonance imaging (MRI): Detailed images of the heart are created using magnetic waves. A dye may be injected to discern the blood vessels and the heart. The aorta’s size can be known.
  • Cardiac catheterization: A thin tube inserted via an artery in the groin or the arm is guided to the heart. It is employed to assess the condition of the heart. If a dye is injected into the arteries, blockages may become evident on x-rays.
  • Computerised tomography (CT) scan: An array of x-rays are utilised to form images of the heart valves and the heart. The aortic valve can be analysed in much detail with a CT scan. A dye to discern the blood flow may be injected by the doctors (CT angiography).

Treatment and prevention

Treatment

Mild to moderate valvular stenosis will require a frequent check up visits. Severe stenosis will require surgical replacement or repair of the valve. Surgery is planned only when it becomes severe in nature.

Medications can’t reverse this condition. However, they can ease few symptoms, lower the blood pressure which may aid in slowing down the development of aortic valve stenosis.

Procedures employed for repair or replacement of the valve include:

  • Transcatheter Aortic Valve Replacement (TAVR): It is a Food and Drug Administration (FDA) approved minimally-invasive procedure employed for repairing the aortic valve. TAVR doesn’t require the old and damaged valve to be removed. Instead, it places a replacement valve in the aortic valve. It is also referred as transcatheter aortic valve implantation (TAVI).

In this procedure, the cardiologist will guide an artificial valve via a catheter through a small incision in the ribs or via an artery in the groin region. The compressed valve is fed via the tube until the aortic valve is reached. The artificial valve is expanded using a balloon inside the ailing aortic valve. Finally, the catheter is taken out.  Blood now flows through the new valve the moment the deflation of the balloon catheter permits blood flow.

Improvement in the circulation of blood is achieved immediately in TAVR, further, it allows faster recovery than open-heart surgery.

  • Aortic valve replacement: It is usually carried out in an open-heart surgery where the narrowed valve is replaced with either a tissue or a mechanical valve. Tissue valve can be from a cow, pig or a cadaver donor. These valves, in turn, will gradually narrow down and require replacement. Sometimes, the individual’s pulmonary valve is used. Metallic valves though last longer, blood clots may form near or on the valve.
  • Rarely, percutaneous balloon valvuloplasty may be carried out in children or in adults at higher risk of surgery.

Prevention

Aortic valve stenosis may be prevented by:

  • Prevention of rheumatic fever: Streptococcal sore throat if left untreated can lead to rheumatic fever.  It can be easily treated with antibiotics.
  • Oral hygiene: A relation between infected gums and heart tissue infection exists. Infected heart tissues can result in inflammation of the heart, narrowing of the arteries and worsen the condition.
  • Limiting strenuous physical activity in individuals diagnosed with aortic valve stenosis can avoid exertion on the heart.

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Complications

Untreated aortic valve stenosis may cause following symptoms and can be fatal:

  • Chest pain
  • Heart failure
  • Arrhythmias
  • Cardiac arrest

Next steps

If one has been diagnosed with aortic valve stenosis, discuss with your doctor the options available for treatment like a TAVR procedure, over traditional surgery.

Red flags

The majority of individuals with aortic valve stenosis do not notice any red flags until the blockage assumes a severe nature.  Contact your physician immediately on noticing any symptoms of fatigue, dizziness and any loss of consciousness.

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References

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  • Aortic stenosis. The Merck Manual for Health Care Professionals. Accessed on 9 Feb. 16. http://www.merckmanuals.com/professional/cardiovascular_disorders/valvular_disorders/aortic_stenosis.html?qt=aortic%20stenosis&alt=sh.
  • Aortic valve stenosis (AVS). American Heart Association. Accessed on 9 Feb. 16. http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/AboutCongenitalHeartDefects/Aortic-Valve-Stenosis-AVS_UCM_307020_Article.jsp.
  •  Aortic valve stenosis. Mayo Clinic. Accessed 9 Feb. 16. http://www.mayoclinic.org/diseases-conditions/aortic-stenosis/basics/treatment/con-20026329
  • Aortic valve stenosis. Radiopaedia.org. Accessed on 9 Feb. 16. http://radiopaedia.org/articles/aortic-valve-stenosis
  • Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis. Circulation. 2002; 106:3006-3008

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